Electron discharge tubes with spherical concentric electrodes



April 18, 1950 P; PATRIARCHE 2,504,224

ELECTRON DISCHARGE TUBES WITH SPHERICAL CONCENTRIC ELECTRODES Filed March 6, 1947 2 Sheets-Sheet 1 Fig! ffens April 18, 1950 P. PATRIARCHE ELECTRON DISCHARGE TUBES WITH SPHERICAL CONCENTRIC ELECTRODES Filed March 6, 1947 2 Sheets-Sheet 2 INVENTOR PIERRE PA TR/ARCHE AGENTS Patented Apr. 18, 1950 ELECTRON DISCHARGE TUBES WITH SPHERIGAL .CONCENTRIC ELECTRODES PierrePatriarche, Ifaris, France, assignor to SocieteFranca se Rad o Elcctrique, acorporatlon Application March 6, 1947, Serial No. 732,736. In France February 22, 19.46

Section}, PublicLaw 690, August 8, 1946 Batent expires February 22, 1966" 9. Claims. (Cl. 250-9275) In discharge tubes it isessential for the electron stream emitted by the cathode to have the optimum spatial distribution such that the anode, as 'well as the intermediate electrodes, can operate under the most efiicientconditions. Such distribution obviously, is conditioned by the shape of the cathode element which generates the electrons, but; it is, also, independent of the shape of the other electrodes and, in particular, of the shape of the anode which is subjected to the electronic bombardment.

Now, the standard shape for the anode is either a cylinder of revolution or, more often, a right angled parallelepipedwith more or less fiat faces and with more or less roundededges all according to theshape or the construction of the cathode, which is generally located in the central region of the tube. On the other hand, for technical reasons. associated with the closing process. the glass, bulb which, limits the space enveloped by the tube has to be a bodyof revolu tion and, owing to this fact, cannot follow. the shape .of the anode.

Furthermore, thedistance between theanode andtheglassof the envelopeis governed: by the conditions. of radiation from the anode, i. e. by the power dissipated, which is afunction of the area of the anode. Consequently, the diameter-D (Fig. 1) ofthe cylindrical portion of the'glass envelope E of--the.tube, which surroundsthe-anode A, becomes largerasthe maximum diagonal d of the straight section of the-anodeism-creased; i. e. for a given perimeter of the straight section, the anode is .of flatter shape.

Suchshapes .of electrodesas are adoptedpin the usualthermionictubes have, therefore, a double drawback. Not'only do they fail toprovidethe conditions necessary for optimum distribution of the electron stream but they. also require the use of glass envelopes of; unnecessarily large. volume.

Thepresent. invention has preciselyfor its. ob ject to modify the shape; of the electrodes of the tube in .sucha manner that; .while providing an efli-cient distribution of the eleetronistream, those portions of theenvelope whose; presence. in the tube is to be explainedonly bythe. technical re+ quirements of closing are completely eliminated. In this way asubstantial reduction in the overall dimensions of the tube is secured. The said invention is based onthe discovery that-'thesube stitution, in a discharge tube, of the parallelepipedic anode .by av spherlcalranode of the same area, permits-of a considerable reduction (oi the order of:40%) in. the-uselesslyhighvolumetric u 2. content required in a tube envelope 'housing a parallelepipedicanode.

According tothe invention, in'addition to the spherical anode, the cathode and; all the other electrodes of the tube are also of spherical shape and all electrodes areconcentrically and symmetrically mounted on amedial disc-of insulating material; finally, the whole arrangement is enclosed in a glass envelope, which islikewisespherical and is concentric with the electrodes, the leads from saidelectrodes-being located in a-medial plane of the envelope.

Under these conditions, it is obvious, in view of the symmetrical arrangement that, in the space limited by the cathode and the anode, which are both spherical and concentric, the electron stream is distributed in the most eflicient manner.

On the other hand, as regards the dimensioning of the electrodes, it'is known that the output power of the-tube depends on the area of the cathode and that, from the predeterminedval-ues given for the output power and the dissipated power, are deduced the values of the areas of the cathode and of-the anode and,- consequently, their radii; from the foregoing values the radii of the intermediate electrodes can then'be calculated;

By way of a non-limitativeexample, a description will-now be given of a'construction accordingto the invention, this construction being illustrated in the accompanying drawings in which:

Fig; 1 is a. diagrammatic view in perspective used to aid in distinguishing theprincip'les of this invention from those of the prior art;

Fig. 2' is a diagrammatic; view partly; in section of the electrode arrangement, accordingto'v the invention;

Fig. 3 is an elevationalrview of the-baseused for supporting electrodes;

Fig. 4 is a plan view cf'the electrode arrangement showing the screendividing the tube along a diametral plane andzis taken on-lines: C'.D'o1- Fig. 5;

Fig. 5 shows a sectional elevational view taken. on lines A B of Fig. 4.

A disc of insulating material, I, supportsin a central aperture Ia, the spherical cathodeCand its internal heating elementF. Concentric with. thesaid cathode C and mountedonthe-same disc I are the grids G1, G2 Gn, and also the anode A; in the figure, only the first grid G1 and=the last 'G'n have been shown.

In order to allow the leads from the various electrodes to emerge from the envelope, the disc I comprises in reality, two contiguous discshetween which the said leads areheld=r-igidly-in the diametral plane of the tube, before the external spherical envelope is sealed. The said envelope itself is formed by two hemispherical glass capes E, E, which are fixed together edge to edge. The sealing in of the outgoing leads is,

on the other hand, efiected by hot-pressing between two external nipples, moulded integrally with the two caps E, E, when the tube is being closed.

Apart from the advantage of the reduction in bulk which is obtained by the use of electrodes of spherical shape, the design according'to the invention also has the advantage of enabling the manufacture of all the electrodes to be effected by means of simple stamping operations. In this .respect, the simplification is particularly notice- :able in the manufacture of reticulated grids. Such grids are constructed, in the shape of a cap, from wire gauze; the cap M (Fig. 3) is then provided at its base with a suitable ring R and with an appropriate system of fasteners K, K enabling the ring to bear accurately against the trued surface of the medial disc I.

It follows, in particular, that, with the design according to the invention, it is possible to ensure extremely accurate assembly of the elements of the discharge tube with reference to the medial disc I, by taking as a datum plane each of the two flat surfaces of said disc.

Finally, owing to the fact that such a tube, according to the invention, comprises two identical parts which are located symmetrically with respect to the double medial support I, there is nothing to prevent the said two parts from being made independent, by separating them by means of an electrostatic screen S interposed between the two insulating discs of the support I. The heater type cathode is connected to the said screen and separate leads are provided for two electrodes of the same denomination. A double tube is thus obtained which can be exactly symmetrical as regards its two halves.

The advantages which accrue from the shape of the electrodes proposed by the invention will obviously have their maximum effect if such shape is exactly spherical. Yet these advantages will still subsist in part if the electrodes, instead of being truly spherical, have the shape of a closed convex surface having at least one plane of symmetry. Of course, the invention also covers thermionic discharge tubes constructed with electrodes of this latter type.

I claim:

1. A spherical electronic discharge tube hav "ing a spherical, indirectly heated cathode, other electrodes cooperating therewith, said 'cooperatring electrodes being spherical, concentric with :said cathode and each constituted by two identical half-sections mounted on a common, insulated, annular support, means mounting said cathode and support so as to be centered on the cathode, the said support also serving to support rigid, rectilinear connecting leads for the electrodes, and the inner diameter of said annular support being greater than the diameter or" the cathode.

2. Electronic discharge tube having a spherical, indirectly heated cathode, other electrodes cooperating therewith, said cooperating electrodes being spherical, concentric with said cathode and each constituted by two identical halisections mounted on a common insulated, annular support centered on the cathode, the said support also serving to support rigid, rectilinear connecting leads for the electrodes, and the inner 4 diamete of said annular support being greater than the diameter of the cathode, said tube having a hermetically sealed, spherical envelope, concentric'with the cathode and supported in spaced relationship to said electrodes and traversed by said rigid connecting leads.

3. Electronic discharge tube having a spherical, indirectly heated cathode, other electrodes cooperating therewith, said cooperating electrodes being spherical, concentric with said cathode and each constituted by two identical halfsections mounted on a common insulated, annular support centered on the cathode, the said support also serving to support rigid, rectilinear connecting leads for the electrodes, and the inner diameter of said annular support being greater than the diameter of the cathode, said insulating support, having plane parallel surfaces, being constituted by two identical half portions, the contacting surfaces thereof being provided with grooves permitting passage of said rigid connecting leads.

4. Electronic discharge tube having a spherical, indirectly heated cathode, other electrodes cooperating therewith, said cooperating electrodes being spherical, concentric with said cathode and each constituted by two identical halfsections mounted on a common insulated, annular support centered on the cathode, the said support also serving to support rigid, rectilinear connecting leads for the electrodes, and the inner diameter of said annular support being greater than the diameter of thecathode,the two identical halfsections of each electrode being individually surrounded by an annular base, said base being provided with metal tongues, and corresponding slots in said support adapted to receive said tongues and to support said base.

5. Electronic discharge tube having a spherical, indirectly heated cathode, other electrodes cooperating therewith, said cooperating electrodes being spherical, concentric with said cathode and each constituted by two identical halfsections mounted on a common insulated, an-

nular support centered on the cathode, the said support also serving to support rigid, rectilinear connecting leads fo the electrodes, and the inner diameter of said annular support being greater than the diameter of the cathode, said tube having a hermetically sealed, spherical envelope, concentric with the cathode and constituted by two identical, hemispherical segments, the contacting edges of said segments being beaded and traversed by said rigid connecting leads.

6. Electronic discharge tube having a spherical, indirectly heated cathode, wherein the electrodes cooperating with the cathode are spherical, concentric therewith and each constituted by two identical half-sections mounted on a common, insulated, annular support centered on the cathode, said support comprising a metal annulus having both plane surfaces covered with a uniformly thick insulating material, the said support also serving to support rigid, rectilinear connecting leads for the electrodes, and the inner diameter of said annular support being greater than the diameter of the cathode.

7. Electronic discharge tube according to claim 6 wherein the said metal annulus is connected to the cathode by at least three radial tongues spaced evenly around the inner edge of said annulus.

8. Electronic discharge tube according to claim 6 having a hermetically sealed, spherical envelope, concentric with the cathode and connected to said annulus by said rigid connecting leads, said leads being located in the median plane of said annulus.

9. In an electronic discharge tube bounded by a, gas-tight spherical envelope of two parts united by junction flanges, an indirectly heated spher ical cathode concentric with the envelope, electrodes likewise spherical enveloping said cathode, concentric with the latter and constituted individually by two identical halves, means enabling external connections of the cathode, its heating circuit and the two halves of each enveloping electrode, said means comprising at least two annular insulating disks of like contour with plane and parallel faces superposed one on i the other and having interior diameters larger than that of the cathode, and centered on said cathode together with means comprising at least three projections for connecting said disks and cathode, rigid conductors radially connected to the electrodes, fixed in one of the faces of the REFERENCES CITED The following references are of record in the 10 file of this patent:

UNITED STATES PATENTS Number Name Date 1,391,671 Donisthorpe Sept. 27, 1921 1,628,982 Hulsizer May 17, 1927 1,752,132 Wilkerson Mar. 25, 1930 1,903,144 Spanner et al Mar. 28, 1933 2,030,187 Salzberg Feb. 11, 1936 2,203,249 Bohme June 4, 1940 2,416,799 Goodard Mar. 4, 1947 

